In the field of recent radiography such as mammography, tomosynthesis imaging has come to be employed as a method of separating information on an object in the depth direction of the object. In tomosynthesis imaging, a plurality of images are acquired by applying X-rays to an object from a plurality of angles, and the plurality of images thus acquired are reconstructed into a tomographic image.
Japanese Patent Laid-Open No. 2003-325499 discloses a mammotomographic apparatus including a mechanical structure that rotates an X-ray generating tube. Japanese Patent Laid-Open No. 2003-325499 further discloses a method in which a tomographic image of a breast is acquired by exposing the breast with X-rays while changing the angle of exposure within a predetermined range.
However, such a mammotomographic apparatus including a rotating mechanism has a problem in that the acquired image may be blurred because of the rotational movement of the X-ray generating tube during imaging. Such a blur in the acquired image may produce an artifact in a tomographic image obtained by the reconstruction of images. Moreover, noise generated by the movement of the X-ray generating tube sometimes makes the examinee feel nervous during imaging.
Accordingly, a tomosynthesis imaging technique has been proposed in which X-rays are applied to an object from a plurality of angles by sequentially using a plurality of X-ray sources that are held stationary. On the other hand, United States Patent Application Publication No. 2004/0213378 discloses a radiographic apparatus that includes an X-ray source unit in which a plurality of X-ray sources are arrayed at predetermined intervals, and a shielding member unit having a plurality of apertures provided in correspondence with the X-ray sources that are arrayed.